// Copyright 2014 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#include "content/common/service_worker/service_worker_utils.h"

#include <string>

#include "base/command_line.h"
#include "base/logging.h"
#include "base/strings/string_util.h"
#include "content/public/common/origin_util.h"

namespace content {

namespace {

    bool PathContainsDisallowedCharacter(const GURL& url)
    {
        std::string path = url.path();
        DCHECK(base::IsStringUTF8(path));

        // We should avoid these escaped characters in the path component because
        // these can be handled differently depending on server implementation.
        if (path.find("%2f") != std::string::npos || path.find("%2F") != std::string::npos) {
            return true;
        }
        if (path.find("%5c") != std::string::npos || path.find("%5C") != std::string::npos) {
            return true;
        }
        return false;
    }

} // namespace

// static
bool ServiceWorkerUtils::ScopeMatches(const GURL& scope, const GURL& url)
{
    DCHECK(!scope.has_ref());
    return base::StartsWith(url.spec(), scope.spec(),
        base::CompareCase::SENSITIVE);
}

// static
bool ServiceWorkerUtils::IsPathRestrictionSatisfied(
    const GURL& scope,
    const GURL& script_url,
    const std::string* service_worker_allowed_header_value,
    std::string* error_message)
{
    DCHECK(scope.is_valid());
    DCHECK(!scope.has_ref());
    DCHECK(script_url.is_valid());
    DCHECK(!script_url.has_ref());
    DCHECK(error_message);

    if (ContainsDisallowedCharacter(scope, script_url, error_message))
        return false;

    std::string max_scope_string;
    if (service_worker_allowed_header_value) {
        GURL max_scope = script_url.Resolve(*service_worker_allowed_header_value);
        if (!max_scope.is_valid()) {
            *error_message = "An invalid Service-Worker-Allowed header value ('";
            error_message->append(*service_worker_allowed_header_value);
            error_message->append("') was received when fetching the script.");
            return false;
        }
        max_scope_string = max_scope.path();
    } else {
        max_scope_string = script_url.Resolve(".").path();
    }

    std::string scope_string = scope.path();
    if (!base::StartsWith(scope_string, max_scope_string,
            base::CompareCase::SENSITIVE)) {
        *error_message = "The path of the provided scope ('";
        error_message->append(scope_string);
        error_message->append("') is not under the max scope allowed (");
        if (service_worker_allowed_header_value)
            error_message->append("set by Service-Worker-Allowed: ");
        error_message->append("'");
        error_message->append(max_scope_string);
        error_message->append(
            "'). Adjust the scope, move the Service Worker script, or use the "
            "Service-Worker-Allowed HTTP header to allow the scope.");
        return false;
    }
    return true;
}

// static
bool ServiceWorkerUtils::ContainsDisallowedCharacter(
    const GURL& scope,
    const GURL& script_url,
    std::string* error_message)
{
    if (PathContainsDisallowedCharacter(scope) || PathContainsDisallowedCharacter(script_url)) {
        *error_message = "The provided scope ('";
        error_message->append(scope.spec());
        error_message->append("') or scriptURL ('");
        error_message->append(script_url.spec());
        error_message->append("') includes a disallowed escape character.");
        return true;
    }
    return false;
}

// static
bool ServiceWorkerUtils::AllOriginsMatchAndCanAccessServiceWorkers(
    const std::vector<GURL>& urls)
{
    // (A) Check if all origins can access service worker. Every URL must be
    // checked despite the same-origin check below in (B), because GetOrigin()
    // uses the inner URL for filesystem URLs so that https://foo/ and
    // filesystem:https://foo/ are considered equal, but filesystem URLs cannot
    // access service worker.
    for (const GURL& url : urls) {
        if (!OriginCanAccessServiceWorkers(url))
            return false;
    }

    // (B) Check if all origins are equal. Cross-origin access is permitted when
    // --disable-web-security is set.
    if (base::CommandLine::ForCurrentProcess()->HasSwitch(
            switches::kDisableWebSecurity)) {
        return true;
    }
    const GURL& first = urls.front();
    for (const GURL& url : urls) {
        if (first.GetOrigin() != url.GetOrigin())
            return false;
    }
    return true;
}

// static
bool ServiceWorkerUtils::IsMojoForServiceWorkerEnabled()
{
    return true;
}

bool LongestScopeMatcher::MatchLongest(const GURL& scope)
{
    if (!ServiceWorkerUtils::ScopeMatches(scope, url_))
        return false;
    if (match_.is_empty() || match_.spec().size() < scope.spec().size()) {
        match_ = scope;
        return true;
    }
    return false;
}

} // namespace content
